According to the specification for `pkg.browser`, there is no reason for us to use this field as the package itself it only for browsers (or any environement with a DOM). Without the field, ESM-compliant transpilers/bundlers will pick `module`, and the others will pick `main`.
https://github.com/defunctzombie/package-browser-field-spec
"name": "foundation-sites",
"version": "6.4.3",
"main": "dist/js/foundation.js",
- "browser": "dist/js/foundation.js",
"module": "js/foundation.js",
"jsnext:main": "js/foundation.js",
"typings": "dist/js/foundation.d.ts",